Section 572.164 - Thorax assembly and test procedure(a)Thorax (upper torso) assembly. The thorax consists of the part of the torso assembly shown in drawing 167-2000 (incorporated by reference, see § 572.160 ).(b) When the anterior surface of the thorax of a completely assembled dummy (drawing 167-2000) that is seated as shown in Figure S1 is impacted by a test probe conforming to 49 CFR 572.127(a) at 6.71 ±0.12 m/s (22.0 ±0.4 ft/s) according to the test procedure specified in 49 CFR 572.124(c) : (1) The maximum sternum displacement relative to the spine, measured with chest deflection transducer (specified in 49 CFR 572.124(b)(1) ), must be not less than 38.0 mm (1.50 in) and not more than 46.0 mm (1.80 in). Within this specified compression corridor, the peak force, measured by the probe in accordance with 49 CFR 572.127 , must be not less than 1205 N (270.9 lbf) and not more than 1435 N (322.6 lbf). The peak force after 12.5 mm (0.5 in) of sternum displacement, but before reaching the minimum required 38.0 mm (1.46 in) sternum displacement limit, must not exceed an upper limit of 1500 N.(2) The internal hysteresis of the ribcage in each impact as determined by the plot of force vs. deflection in paragraph (b)(1) of this section must be not less than 65 percent but not more than 85 percent.(c)Test procedure. The thorax assembly is tested as specified in 49 CFR 572.124(c) .